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99 SN GT40 Fuel Supply

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    Posted: April-29-2012 at 4:21pm
At the end of last seaon, after a couple passes through the course, my engine died when I applied power to take off. It would idle fine, but would die with a gasping sound every time I gave it gas. Couldn't even power up on the trailer.

Since that time, I booght a pressure gauge and have observed some very strange readings. It will run about 35 psi, then fluctuate widly and go to zero. I removed the Regulator hose and saw it momentarily jump to 40 psi, then go through all the ups and downs as before.

The pumps do not always prime, so I have been inclined to think it is a power issue to the pumps. I replaced the relays, as I had sufferred through that diagnosis two years ago, and have a two year old low pressure pump, ant-syphon valve, and kill switch to thank for that one.

The plugs and distributor cap and rotor are new.

The hi pressure pump and filter are new along with the FCC housing, as I developed a gas leak through the fitting on top of the old FCC when I was checking the hi pressure pump and filter. (that was a $450 ouch). I also replaced the 15 amp circuit breaker, as that seemed like it was frozen.

I completely drained the fuel tank when I repacked the rudder this spring, so I am pretty sure nothing in the tank is plugging the line. I have no in line filter, only the one in the fcc.

I have followed the electrical lines back to the fuses, and all connections seem clean and tight.

I want to jump the low pressure pump direct to the battery, and am making up some alligator clips to go direct to the low pressure pump to see if this makes a difference.

Does anyone know what terminal on the low pressure pump is positive vs negative? I am thinking I need to run off the battery to the positive post and vice versa for negative. I am thinking this might confirm that the low pressure pump is good.

The other question is what else can I look at that would cutoff power to the pumps? I replaced the relay this year, as I have two spare ones. That made the pumps prime, and I thought I might have fixed it like last time, but, that was just a coincidence of the problem.

What is odd is that the engine will not take gas, consistently. If the pumps are randomly running, you would think that I could at least get rpms randomly.

This one is a real head scratcher. The guys from Ski Dim and White Lake have been great, but we are just shooting at the sky right now, and the season is right around the corner. My dealer is no longer in business, and the next guy is 2 hours away, and I don't know him well.

Any ideas?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote 8122pbrainard Quote  Post ReplyReply Direct Link To This Post Posted: April-29-2012 at 4:59pm
Al,
Others I'm sure can comment. I can help with one item regarding the pump polarity. Just get the Ohm meter out and check which lead on the pump is ground.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMB Quote  Post ReplyReply Direct Link To This Post Posted: April-29-2012 at 5:28pm
8122, I am somewhat electrically challenged. I have a meter, but really don't know how to use it very well.

How would I check for ground?

I have turned a few wrenches in my time, but not dealt with a lot of electrical stuff. My dad was the electrician, plumber, welder, etc....

Thanks
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMB Quote  Post ReplyReply Direct Link To This Post Posted: April-29-2012 at 5:30pm
Oh yea, I pulled the oil pressure sensor (smaller bell shaped senser) wire off and it is not the problem. I have read that a faulty sensor can send it into limp mode and shut down the pumps.

This boat has about 400 hours on it, looks like new, and has been a really strong runner up until this little speed bump..

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Post Options Post Options   Thanks (0) Thanks(0)   Quote 8122pbrainard Quote  Post ReplyReply Direct Link To This Post Posted: April-29-2012 at 6:36pm
Al,
Set the meter to any Ohm range. What happens when you touch the two probes?

If one of the probes was grounded on the block and then you touched the ground wire feeding the pump with the other probe, what should happen?

What have you been using the meter for?


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Post Options Post Options   Thanks (0) Thanks(0)   Quote harriss28 Quote  Post ReplyReply Direct Link To This Post Posted: April-29-2012 at 10:49pm
Where do you take your boat in NW Ohio? I am in NE PA so we are neighbors. Im always looking for new lakes and camping.

As Pete said, set to Ohm range. Touch the probes together, and note the reading. The reading will be the same when a probe is grounded to block and the other on ground feed wire.



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Post Options Post Options   Thanks (0) Thanks(0)   Quote lewy2001 Quote  Post ReplyReply Direct Link To This Post Posted: April-29-2012 at 11:07pm
Al you can make both pumps run by shorting the end terminal of the STO connector to ground (ECC Test connector above relays). You should have 39 +- 3psi with key on engine off and 31 +- 3psi at idle. With the vacuum hose removed at regulator and engine running you should see max pressure mine reads almost 44psi.

I would also check the volume of fuel the low pressure pump puts out.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMB Quote  Post ReplyReply Direct Link To This Post Posted: April-29-2012 at 11:38pm
Lewy, what is the yellowish square-looking thing in the middle of your jumper lead?

This looks simple enough if I use an alligator clip with bare wire on the other end.

I am 99% sure this is an electrical short some where, so if the pump runs or primes, then this would be a good indication I am on the right track.

Thanks
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMB Quote  Post ReplyReply Direct Link To This Post Posted: April-29-2012 at 11:41pm
I am just south of Toledo. The lake is alongside the Ohio turnpike. Look at Google Ski Sites, it is The Slalom Club (I know, real creative name).

My dad gave me the meter. I guess I have tested batteries with it, and that is about the extent of me using it.....
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Post Options Post Options   Thanks (0) Thanks(0)   Quote lewy2001 Quote  Post ReplyReply Direct Link To This Post Posted: April-29-2012 at 11:53pm
Originally posted by AMB AMB wrote:

Lewy, what is the yellowish square-looking thing in the middle of your jumper lead?

This looks simple enough if I use an alligator clip with bare wire on the other end.

I am 99% sure this is an electrical short some where, so if the pump runs or primes, then this would be a good indication I am on the right track.

Thanks


Not my photo but it is just a fuse in case there is a short to power somewhere else in the circuit.

I have just used a piece of wire but the the inline fuse is a good idea.

As a matter of interest do you still have the large black fuse in your battery box?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMB Quote  Post ReplyReply Direct Link To This Post Posted: April-30-2012 at 12:13am
No fuse on my battery line. I have seen that has caused intermittent problems for some, but I don't have one. Good thought though.    

Here is a link to a video I made of the boat running in the driveway. I removed the regulator hose, and this time, the pressure had dropped to zero, but you can hear the rpms pick up a little. When I did this when the pressure was at 35 lbs, it jumped to 40.

You can hear the pumps sucking air as the pressure drops.

The boat ran great and then viola, this is what it did on the lake on the last ski ride for last season.

http://www.youtube.com/watch?v=0hihpHcuNvY

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Post Options Post Options   Thanks (0) Thanks(0)   Quote slmskrs Quote  Post ReplyReply Direct Link To This Post Posted: April-30-2012 at 12:22am
One way to "rough" confirm the low pressure pump is working (when you jump the ECC test connector, this makes both pumps run with the key on but engine off--this is easier than jumping the pumps directly), is to listen for gas returning to the tank. The low pressure pump pumps from the tank to the FCC, and the overage flows back into the tank and you can hear it splashing (when the engine is off and the pumps are on). While using the jump, you can also isolate each pump by unplugging the other one (since they are on the same circuit). That way, with nothing but one pump on at a time, you should be able to hear if it is going on and off, etc. You can also check the voltage at the pump by using your tester in the DC volts setting and putting one lead on the hot side of the pump connector and the other side to ground and then turning on the pump circuit (don't do this with your multi-tester in Ohm setting, or you will either blow a fuse or kill the meter).

Also, since you said the pressure is jumping all over the place, it would be interesting to check the pump voltage when the pressure is jumping. Of course, if you jump it,
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Post Options Post Options   Thanks (0) Thanks(0)   Quote slmskrs Quote  Post ReplyReply Direct Link To This Post Posted: April-30-2012 at 12:23am
Ignore the last paragraph. I was going to delete it after I changed the paragraph above it. :-)
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMB Quote  Post ReplyReply Direct Link To This Post Posted: April-30-2012 at 12:54am
I will try this out this week. If I can determine that the pumps are fine, then I can just focus on the electrical side of things, again, not my strongest area!

Thanks
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Post Options Post Options   Thanks (0) Thanks(0)   Quote slmskrs Quote  Post ReplyReply Direct Link To This Post Posted: April-30-2012 at 1:10am
There are a number of us GT-40 folks lurking on the forums (a number of them have quite a bit of experience with troubleshooting the ECC, etc.). So I'd say you are in good hands (keeping in mind how much you are paying for this advice....)   
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMB Quote  Post ReplyReply Direct Link To This Post Posted: April-30-2012 at 1:17am
After my issue with the fuel pump relay switch, I thought I had a better than average comprehension of the fuel delivery system. It would have been better if the relay would have just quit. By going bad intermittantly, it gave me a lot of false positives when I was trouble-shooting.

This problem is elusive, and I have already dropped some big bucks, mainly the FCC. You can't buy just the electrical plug for it anymore, and I didn't think JB Weld was really safe, but I thought about it...

I appreciate all the input. I guess I am too stubborn to drag it up to Silver Spray, at least I am learning something.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote slmskrs Quote  Post ReplyReply Direct Link To This Post Posted: April-30-2012 at 1:26am
Sorry, I just now saw the video.

First, what is that hissing noise we hear when the pressure gauge is climbing back up to normal pressure? Where is that coming from?

Second, something is weird with your pressure gauge, how it is hooked up, or something. If the pressure in the rails drops to zero, the engine dies. It will not run if there is no pressure at the rails (the injectors open, but there is no pressure to push the gas into the manifold).

So something is weird since it is still running (albeit loping) with no pressure indicated, but it will be helpful to understand where that hissing is coming from. Note: It sounds similar to the loping issue that a number of us are dealing with (with some, there is cold start loping, and with others, it is hot restart loping). However, with my loping, the PSI stays between 32 and 40. So I don't think it is related (a number of us are working through this), but the loping idle in your video is very similar.

Anyway, make sure your gauge is on securely (tight), let us know what that hissing noise is when the pressure is moving back up. Then use the jump that Mark showed you; that will keep the pumps on with the ignition on (instead of them turning off after one second). You can then test each one (low pressure by the sound of fuel returning), and high pressure by your pressure gauge.

Oh, and you said it sounded like the pumps were sucking air. I don't know if you could hear that with the pumps on and the engine off, but I'm pretty sure there is no way you would be able to hear anything like that if the engine is running. I'll watch/listen to the video a few more times in the next day or so to see if I can pick up anything.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMB Quote  Post ReplyReply Direct Link To This Post Posted: April-30-2012 at 1:45am

I was told by one of the guys at Skidim that when the pumps are starving they make a lot of noise. I have not been able to pinpoint where this noise is coming from. I do know that it was making that noise out on the lake. It is pretty loud with the box up!

I have triple-checked the pressure gauge, as I too thought how in the heck can this engine keep running with no pressure. I thought maybe there is just enough coming through the pumps to keep it loping badly along. While it does this, it exhausts some black smoke as well, and smells like it is running rich. I wouldn't believe that with the pressure dropping off to zero, but I kid you not, it smells like it is running rich.. My guess is that it is almost stalling so not firing on all cylinders, and just enough gas is not getting burned up when it doesn't fire, so it is just burning it off like a rich engine situation.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote lewy2001 Quote  Post ReplyReply Direct Link To This Post Posted: April-30-2012 at 4:22am
Like slmskrs(Gordon) mentioned not sure what sort of connection you have on your pressure gauge but zero pressure and engine still running is weird. I assume it is connected to Schrader valve on fuel rail. I remove the valve inside of this connection before I hook my gauge up as the connection does not depress the valve properly.

I assume the hissing noise is there when you open the throttle? With the pumps jumped to run you should hear the pumps run without the engine and see if that noise is still there.

It sounds like a vacuum leak but it might be that the mixture is way to lean. When you removed the vacuum hose to pressure regulator it should have leaned the mixture out and increased idle speed if there was enough fuel available. So it seems like it is starving for fuel. But then you mention black smoke and smell of running rich.

Could it be a poor spark problem?

The TFI module is a known problem area on these engines check connections to TFI module and pull a plug and check for nice fat spark.

Confirm connection and correct reading of pressure gauge and get back to us.

It is a nice demonstration of the engine idle loping that Gordon is chasing. I have had that a few times myself. Sounds like a engine with a big camshaft and lots of overlap.

By the way nice colour scheme and don't let the wife know that the hot water out of the exhaust is what killed the grass.

If you're going through hell, keep going

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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMB Quote  Post ReplyReply Direct Link To This Post Posted: April-30-2012 at 11:13am
Lewy2001, I am pretty sure I am on the Schrader valve. I have triple-checked the connection due to no pressure and engine still running. If I take out the valve stem, will gas come out? Will I need to take my adapter off my gauge (that depresses the core?).

The noise appeared when I was accelerating at the end of last year, and upon observation with the box up, seems to be when it loses pressure or bounces around. When I start it sometimes and it reads 35 psi, the idle is fine and no noise. When I first removed the vacume line, pressure jumped from 35 to 40psi and stayed there until the symptoms showed up. In the video, pressure had already dropped off and when I took the vacume line off, you can hear the rpm pick up a bit.

I replaced the plugs and cap/rotor a few weeks ago, just to rule them out. I have not checked spark, but when we ran it on the water a couple weeks ago, it sounded like a 3,000 rpm engine that someone was turning the ignition off and on. Yes, I took the dash off and checked all fittings on the ignition switch.. I have not jumped the kill switch, but that is only 2 years old.

I can check the MAPP and TFI connections, is there any way to tell if they are bad?

Yea, it sounds like my old Mustang when it lopes, too bad it doesn't run like it!

Thanks on the color, Masters Blue is one of my favorites, I guess I am a traditionalist.

I don't like to have water puddle on the driveway when I am in and out of the boat, because I don't want to get my carpet wet, so the grass takes a hit. It grows back, antifreeze is worse.

Thanks for the ideas.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote lewy2001 Quote  Post ReplyReply Direct Link To This Post Posted: April-30-2012 at 12:08pm
Al, no fuel should come out of the Schrader connection with the valve removed and the gauge in place. Leave the adapter on the end of the gauge as it is. This rules out any problem with the gauge fitting opening the valve. This is for testing purposes only. Would not leave it for any length of time that way.

Need to confirm those pressure readings first both at idle and with the jumper on STO connector.

Also check the output of low pressure pump as mentioned previously. This is achieved by disconnecting the high pressure pump electrical connections at FCC. Remove fuel hose from low pressure pump to FCC and place it in a container. Install the jumper to STO terminal it should pump about a US Quart in around 15-20 seconds. I have a Schrader valve on top of my FCC not sure if the new FCC you fitted still has one. The reading should be the same on the fuel rail anyway.

If you have a electrical problem as you suspect the grounded jumper on STO connector should help you troubleshoot. You will hear the pumps running I would wiggle all the connections on both the fuel pump and EEC relays plus tap the connections on all 3 cct breakers located on computer bracket. If the pumps stop you will know which connection to investigate further. If you have not already downloaded the GT40 manual from the reference section do so and printout page 281 and 282. It gives you the wiring diagram for the fuel pump operation.



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Post Options Post Options   Thanks (0) Thanks(0)   Quote M3Fan Quote  Post ReplyReply Direct Link To This Post Posted: April-30-2012 at 12:14pm
If my GT40 starts loping this summer, I'm blaming you guys for talking about it so much and jinxing it.

Seriously though, as these powerplants start getting past 15 years old it's going to be interesting to see how often we start talking about them! I've seen more GT40 threads over the past few months than I have since the site launched.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote slmskrs Quote  Post ReplyReply Direct Link To This Post Posted: April-30-2012 at 1:19pm
Originally posted by M3Fan M3Fan wrote:

If my GT40 starts loping this summer, I'm blaming you guys for talking about it so much and jinxing it.

Seriously though, as these powerplants start getting past 15 years old it's going to be interesting to see how often we start talking about them! I've seen more GT40 threads over the past few months than I have since the site launched.


Well, I'm not going to mention that I joined in January.......       Actually, other than the loping issue (which I've had for probably a decade) and the water jacket cracks in the heads (typical of a GT40), I have had to replace my low pressure pump and clean out a small screen mesh in the top hose connection at the fuel tank......in almost 1,400 hours. It has been incredibly reliable, including the electronics. Head cracks are irritating as it is a known problem, but other than that, I think it is an extremely reliable powerplant (much better than my old carb'ed PCM 351 in my old boat).

AMB: A couple of additional questions while we're waiting for the results of your next set of tests.

Is there any difference between cold running and warm running? In other words, does this happen when you first start it (with a hose), or does it need to warm up before it starts doing it?

How long after you start it does it start having the problem? I saw in the video how when the pressure is at the correct PSI range, the engine runs correctly.

So I'm interested in the timing of when it starts.   For example, if it is doing it and you shut it off and then restart, does it continue, or does it run fine for a little bit before it does it again?

If it does it fairly soon after you start, it will be interesting to see if you hear the pump noise and see the pressure drop about the same time when you jump the pumps.

Also, as Mark said, it is a good idea to remove the shrader valve to hook up the gauge as I experienced the same problem (not properly depressing the valve). Make sure you have no pressure before you do it. I managed to get it tight enough to work, but you do not want to shear the valve off.

Let us know on the above, and also the results when you jump the pumps (do you hear gas splashing back into the tank, does the sound happen (and pressure drop) when only the pumps are running, if you hear splashing, what is the flow of the low pressure pump (filling a container), etc.

Speaking of starving, a problem I had previously which had different symptoms is that there is a small screen mesh in the top of the tank where the inlet hose connects. That had actually gotten plugged with dirt, etc., and it finally got so bad that while it would idle, we couldn't cruise for very long, and finally couldn't even drive through the course without it cutting out. Long story short, it ended up being that little screen--pulled it out, cleaned it up, put it back in, and everything was good. I do not recall hearing the type of "starvation" sounds that you have, the engine just stuttered and slowed. Not to say that it didn't make the starvation noise, but since I was at speed when it would happen, there could have been too many other noises to hear it (or I just don't remember....).

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Post Options Post Options   Thanks (0) Thanks(0)   Quote 8122pbrainard Quote  Post ReplyReply Direct Link To This Post Posted: April-30-2012 at 1:27pm
Originally posted by AMB AMB wrote:


I am 99% sure this is an electrical short some where

I haven't noticed if you are blowing any fuses or any wiring is getting hot. Are you sure you have a short?


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bri892001 Quote  Post ReplyReply Direct Link To This Post Posted: April-30-2012 at 2:10pm
If you do get it figured out, could you weigh in here:
edited link:
http://www.correctcraftfan.com/forum/forum_posts.asp?TID=25584&title=poor-mans-gt40-diagnosis

Also, have you confirmed your fuel tank is venting properly, try opening your fuel cap and see if this helps.

Also, you may have one more fuel filter, under the removable floor section behind the motorbox. Some of them have this, some don't. If you do, it is a possible restriction if it's dirty.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMB Quote  Post ReplyReply Direct Link To This Post Posted: April-30-2012 at 2:25pm
All good questions.

I took the tank out of the boat and emptied it and blew air through the pickup. The mesh at the bottom looked clean anyway, but still throught it would be good to blow out.

Also ran with gas cap off, no change.

The thing that leads me to think it is electical is that the pumps don't prime with ignition on. Sometimes they do, and sometimes they don't, and everything I have read is they prime every time. When my pressure dropped to zero, I shut it off and listened, and no prime.

I replaced the relay last week just for kicks, and it primed, so I thought maybe it was a bad relay AGAIN. But I started it up, got 35 psi, and then it wouldn't take rpm and then all the crazy pressure readings.

I am thinking it could just be a bad connection or something, or maybe the low pressure pump is knocking out the relay.

I have two anti-siphon valves, (I replaced one when the relay was bad two years ago), so I put the old one back on, same thing.

I chased the fuel line back to the tank when I repacked my rudder and had the tank out. No extra fuel filter. That wouldn't shut the pumps down electrically, I don't think, even if bad..

I will check into some of these tonight after work.

Thanks!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote slmskrs Quote  Post ReplyReply Direct Link To This Post Posted: April-30-2012 at 9:23pm
Originally posted by AMB AMB wrote:

The thing that leads me to think it is electrical is that the pumps don't prime with ignition on. Sometimes they do, and sometimes they don't, and everything I have read is they prime every time. When my pressure dropped to zero, I shut it off and listened, and no prime.


Sorry, I glossed over the "prime" info you gave and went off looking in other directions. I'd definitely check all of the connections, grounds, etc. especially to the relay and to the ECC since the ECC controls the prime relay. Maybe you're getting intermittent power to the ECC. Also, I don't know where it is, but I'd check wherever the pumps are grounded to. Also make sure your ground connections at the key are good. Poor grounding causes a lot of problems on these (and probably any other) boats.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote lewy2001 Quote  Post ReplyReply Direct Link To This Post Posted: April-30-2012 at 11:41pm
Originally posted by AMB AMB wrote:

The thing that leads me to think it is electrical is that the pumps don't prime with ignition on. Sometimes they do, and sometimes they don't, and everything I have read is they prime every time. When my pressure dropped to zero, I shut it off and listened, and no prime.

I replaced the relay last week just for kicks, and it primed, so I thought maybe it was a bad relay AGAIN. But I started it up, got 35 psi, and then it wouldn't take rpm and then all the crazy pressure readings.

I am thinking it could just be a bad connection or something, or maybe the low pressure pump is knocking out the relay.


Yes the pumps should prime every time you turn on the ignition switch. The ignition switch activates the EEC relay that supplies power to the computer which in turn activates the short prime cycle for fuel pumps. The EEC relay also supplies the power to activate the fuel relay. So it could be either relay or connections. Changing the relay and then it worked sounds like a bad connection that you may have disturbed while changing the relay.

Get that jumper wire on the STO connector and start wiggling wires and connections with the pumps running.

Gordon the main battery earth is on the starter side on bell housing there is another earth point on other side of engine near knock sensor on cylinder head. The earth for the pumps would be going to one of these points.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMB Quote  Post ReplyReply Direct Link To This Post Posted: May-01-2012 at 12:00am
Ok guys, I turned the ignition on and started wiggling. I got back to the STO and just touched it and the pumps primed. I squeezed it together and turned ignition on and off a few times, primed every time and the pressure went to 40psi.

I then took apart the connector and it felt too easy, but I did break the plastic piece on the TEST Connector. I jumped with a wire lead and the pump then kept pumping and I could hear gas dumping in the tank, and pressure was 40 psi.

Trying to remain calm, as I had false positives before.. but holy crap Batman, this has been one PITA!

I do have a question though, there was a smaller gray plug at the top of the pic above, that looks like it just popped out of the STO, and it is sort of hard to see if it should snap in or just rest in there with no purpose. There is another dead end looking larger gray plug, which is a the bottom of the pic above. Do I need to do something with the smaller connector?

Also, I assume White Lake and Skidim carry the Test Connector? The black piece mounted on the plate with a plastic snap in fastener.

THANKS A MILLION GUYS!!! WEATHER IS WARMING UP AND THE BOAT HAS TO GET RUNNING!!!

AB
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMB Quote  Post ReplyReply Direct Link To This Post Posted: May-01-2012 at 12:14am
ok, I can't find the ECC Test Connector on any website. Is this an OEM part from CC?

thanks
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